Is there any point in continuing to learn even if my child can't keep up with schoolwork?

Yes. In common: the meaning of learning isn't only "catching up to the grade level." Learning that, at the child's own pace, increases what's useful in life, what they like, and what they can do has value—it connects to confidence and future options. What the family decides: aiming for "the same content as everyone" or switching to "learning that suits the child" is your choice. A guide: "does the child hold a felt sense of understanding and being able?" "has learning become painful?" Replacing the purpose from "to catch up" to "for this child to grow" gives learning a reason to continue.